Timeline for How did dark matter become a relic?
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| Mar 17, 2017 at 13:49 | comment | added | anna v | Neutrlino annihilation (see this for example) will be very weak . It is the lack of sources when the energy drops below production of parents that is crucial. this is interesting ned.ipac.caltech.edu/level5/Kolb/Kolb5_1.html for axions this astro.princeton.edu/~dns/MAP/Bahcall/node16.html | |
| Mar 17, 2017 at 10:13 | vote | accept | SRS | ||
| Mar 17, 2017 at 10:09 | comment | added | SRS | What is the freeze-out temperature for a dark matter candidate $\chi$? Is it the temperature at which $\chi\chi$ interactions do not have sufficient energy to reproduce heavier particles (which can decay into $\chi$). Or is it the temperature at which the $\chi\bar{\chi}$ annihilation stops? | |
| Mar 17, 2017 at 10:00 | comment | added | anna v | yes , that is the picture | |
| Mar 17, 2017 at 9:20 | comment | added | SRS | So dark matter is the (comparatively) lighter but stable decay products of heavier particles. These heavier particles were in equilibrium at very early epoch. The rate at which these heavier particles decayed into lighter DM particles, was equal to the rate at which DM particles interacted to re-produce them back. But as the Universe expanded and cooled, the DM particles didn't have enough kinetic energy to re-produce back the heavier particles. Moreover, the expansion resulted in the reduced number density and made interaction between DM particles became infrequent. Is that correct? | |
| Mar 17, 2017 at 8:57 | history | edited | anna v | CC BY-SA 3.0 |
clarification
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| Mar 17, 2017 at 8:55 | comment | added | anna v | The dark matter does not decay, it exists as it is the bottom particle. But theparticles that decay to the dark matter axion or neutralino, need high energies to be created in the primordial soup. When the universe has cooled down to the nuclear creation age, they are not generated any longer in large numbers and they decay and then the number of dark matter axions or neutralinos is stable. | |
| Mar 17, 2017 at 8:38 | comment | added | SRS | My question is why should should the DM decay rate be suppressed (if not completely stop) when the temperature of the Universe falls below DM mass. | |
| Mar 17, 2017 at 8:34 | history | answered | anna v | CC BY-SA 3.0 |